Pump



June 24, 1958 Filed June 13, 1955 2 Sheets-Sheet 1 4s INVENTORS E.GUENTHER 52 B D.M.VESPER 30 y F/G. 18 Qt 3;

ATTORNEYS United States Patent 2,840,004 PUMP Application June 13, 1955, Serial No. 514,921 4 Claims. (Cl. 103-152) This invention relates to pneumatically operated pumps.

In various research and industrial operations there is a need for pumps which are capable of delivering accurately measured quantities of fluid and which are safe to use in explosive atmospheres. The present invention is directed toward providing such a pump which is operated solely by pneumatic pressure. The pump of this invention employs a bellows which is alternately compressed by pneumatic pressure and expanded by the force of resilient means, such as a spring. The fluid to be pumped enters the bellows through a first check valve on the expansion stroke and is forced from the bellows through a second check valve on the compression stroke. Pneumatic pressure is applied continuously to the pump. A valve arrangement within the pump is operated by expansion and contraction of the bellows to vent the pneumatic pressure at the end of the bellows compression stroke. The pressure is reapplied to the bellows at the end of the expansion stroke.

Accordingly, it is an object of this invention to provide an improved pump which is operated by pneumatic pressure.

Another object is to provide a bellows pump which employs a minimum number of moving elements.

A further object is to provide a pump which is safe for use in explosive atmospheres. v

Various other objects, advantages and features of the invention shouldbecomeapparent from the following description,- taken in conjunction with the accompanying drawings, in which:

Figure l is a sectional view of the pump of this invention;

Figure 2 is a view'taken-along line 2-2 in Figure 1',

Figure 3 is an elevation view of one of the plungers employed in the pump;

Figure 4 is an elevation view of the second plunger employed in the pump; and

Figure 5 is a schematic representation of a complete pumping system incorporating the pump of this invention. v

Referring now to the drawings in detail, and to Figures 1, 2, 3 and 4 in particular, there is shown a pump which comprises a housing defined by a cylindrical body 11 having a cap 12 secured thereto by a plurality of screws 13. A gasket 15 is interposed between body 11 and cap 12. A base 17 is secured to body ll by a plurality of screws 18. A gasket 19 is interposed between base 17 and body 11. An expansible bellows 21 is positioned within body 11. Bellows 21 is attached at its upper end to a nipple22 which extends upwardly through a central opening in cap -12.' Nipple 22 is secured to cap 12 by a lock nut 23. The lower end of bellows 21 is attached to a plate 24 which is free to move within body 11. A plunger 25 is positioned for movement through body 11 and is attached to plate 24 by a screw 26. Pneumatic pressure external of bellows ice 2 21 compresses the bellows to raise plate 24 and attached plunger 25. A compression spring 28 is interposed between cap 12 and plunger 25 to tend to retain bellows 21 in an expanded position.

A plunger 30 is disposed within a central opening in base 17. A ring 31 is fitted in an annular slot 32, see Figure 3, near the upper end of plunger 30. Ring 31 engages the lower surface of piston 25 and is retained in this position by a plate 33 which is secured to plunger 25 by screws 34. An annular spacing member 35 rests upon base 17 and surrounds the upper portion of plunger 30 to limit the downward movement of piston 25.

Piston 25 is provided with four spaced annular re cesses 37, 38, 39 and 40. A plurality of radial passages 42, 43, 44, and 46 are drilled in base 17 to communicate with the central vertical opening through which plunger 30 is free to move. The outer ends of passages 43, 45, and 44 are blocked by respective plugs 62, 63, and 65. An inlet passage 48 is formed in base 17 to supply pneumatic pressure to actuate the pump. A second vertical opening is drilled through base 17, and a plunger 50 is positionedfor slidable movement therein.

The upper portion of this second opening is plugged bya screw 51 and the lower portion of the opening is plugged by a screw 52. These two screws limit movement of plunger 50 and define chambers 53 and 54 above and below plunger 50, respectively. Plunger 50 is provided with an annular'recess 55. A passage 56 is formed in base 17 to intersect .the vertical opening through which plunger 50 is free to move. Passage 56 communicates at its inner end with a vent passage 57, the latter communicating at its outer end with a vent opening 58. The outer end of passage 56 is blocked by the plug 64. A vertical passage 60 is drilled in base 17 to intersect passages 56 and .44. Passage 60 communicates at its upper end with the interior of body 11 beneath piston 25. Inlet passage 48 extends slightly beyond the central vertical opening in base 17 to form a passage 61.-

Radial passages 70, 71 72 and 73 are drilled through plunger 30, see Figure 3, to communicate with respective recesses 37, 38, 39 and 40. An axial passage 75 is drilled in plunger 30 so that passages 70 and 71 are in communication. The upper end of passage 75 is blocked by a plug 76. A second axial passage 77 is drilled in plunger 30 so that passages 72 and 73 are in corri munication. The lower end of passage 77 is blocked by a plug 78.

Figure 5 illustrates the connection of pump 10 in a pumping system. Fluid to be pumped is directed from a conduit 80 through a check valve 81 and conduits 82 and 83 to the interior of bellows 21 through nipple 22. Conduit 83 is also connected to the inlet of a second check valve 84. The outlet of check valve 84 is connected to a conduit 85. A source of pneumatic pressure to energize the pump is connected to inlet 48 through a conduit 86 having a valve 87 therein. Vent opening 58 is connected to an outlet conduit 88 having a valve 89 therein.

When it is desired to operate the pump, valves 87 and 88 are opened so that the pneumatic pressure is supplied to and exhausted from pump 10. Bellows 21 initially is expanded by the action of compression spring 28. Plunger 30 occupies the illustrated position so that bellows 21 is filled through checkvalve 81 with the fluid to be pumped. The pneumatic pressure applied .to inlet 48 is transmitted through passages 71, 61, 44 and 60 to the interior of body 11 beneath piston 25. -This pressure is also applied to a region exterior of bellows 21 through a vertical passage 91 in piston 25 and plate 33. The pressure forces piston 25 upwardly against the retaining force at spring 28. The upward movement of 56, recess 55 and passage 57. The pneumatic pressure in chamber 53 is vented through passages 43, 71, 36, 70 and 42; Co pressionspring 28,-forces piston 25 downwardly 'to the position illustrated. The second cycle then continues, as described.

While a bellows 21 has been illustrated in valve body 11 it should be apparent that the pump can be operated without this bellows if. passage 91 is, blocked. 'Such an arrangement is generally not as ,satisfactory,.l1owever, because piston 25, needs to be sealed to prevent leakage of fluid between this piston and valve body 11. How

ever, such an arrangement is useful for some applications of the pump.

While the invention. has been described in conjunction with a present preferred embodiment, it should be apparent that it is not limited thereto.

What is claimed is: V

1. A pneumatically operated bellows pump comprising a housing having a chamber therein and .a first fluid inlet in one end thereof; a bellows positioned within said chamber, saidlbellows beingsecured at one end to said one end of said housing so that. said inlet communicates with the interior of said bellows; said housing having first and second passages therein extending in spaced relationship'with one another; means sealing the two ends of said. first passage; a first plunger positioned in said first passage, said first plunger having a circumferential groove therein; a second plunger positioned, in said second passage; means connecting the second end of said bellows to one end of said second plunger; said second plunger having first, second, third and fourth openings therethrough, said first and second openings being connected and'said third and fourth openings being connected; resilient; means urging said bellows to an expanded position and also urging, said fourth opening into communicationwith aregion external of the housing; said housing havinggan inlet opening therein in communication with said second passage, a fifth opening between said inlet opening and first passage, a sixth opening between said, first passage and said chamber external of said bellows, a seventh opening'between a region exterior of said housing and said first passage, an eighth opening between a region exterior of said housing and said second passage, a ninth opening between said second passage and one end of said first passage, and a tenth opening between said second passage and the second end' of said first passage said openings being, positioned so that fluid is transmitted from said inlet opening to said chamber external of said bellows through a path that includes said second opening, said groove and said sixth opening and so that fluid is vented alternately and sequentially through a path that includes said sixth opening and said groove.

2. The combination in accordance with claim 1 further comprising first conduit means communicating with said first fluid inlet, a first check valve in said first conduit means to permit fluid flow into the interior of said bellows within said housing, second conduit means communicating with said first fluid inlet, and a second check valve in said second conduit means to permit fluid flow from the interior of said bellows within said housing.

3. A pneumatically operated bellows pump comprising a housing having a chamber therein and a first fluid inlet in one end thereof; a bellows positioned within said chamber, said bellows being secured at one end to said one end of said housing so that said first inlet communicates with the interior of said bellows; said housing having first and second substantially parallel passages therein; means sealing the ends of said first passage; a first plunger positioned in said first passage, said first plunger having a circumferential groove therein; a second plunger positioned in said second passage, said second plunger having first, second, third and fourth circumferential grooves therein and internal passages connecting said first and second grooves and said third and fourth grooves; means connecting one end of said second plunger to the second end of said bellows so that contractionand expansion of the bellows moves said second plunger through said secondpassage; resilient means urging said bellows to an expanded position; said housing having an inlet opening therein in communication with said second passage, a second opening between said inlet opening and said first passage to communicate with the groove in said first, plunger when said bellows is expanded and said first plunger is in the first end of said first passage, a third opening communicating between said chamber external of said bellows and said first passage adjacent the groovein said first plunger when said first plunger is in the first end of said first passage, a fourth opening communicatingbetween said chamber external of said bellows and said first passage adjacent the groove in said firstplunger when; saidfirst plunger is in the second end of said first passage, .11 fifth opening communicating between the exteriorof said housing andsaid first passage adjacent the groove in said first plunger when said first plunger is in the second end of said first passage, a sixth. opening communicating between said second passage and said first passage adjacent said first end, a seventh opening communicating betweensaid secondpassage and said first passage adjacent said second end, an eighth passage communicating between the exterior of said housing and said second passage, Ya, ninth passage communicating between the exterior of said housing and said second passage, said openings and grooves being positioned so'that said first, second, third and fourth grooves communicate with said seventh inlet, sixth and ninth openings, respectively, when said bellows is expanded and said first, second, third and fourth grooves communicate with said eighth, seventh, inlet and sixth openings, respectively, when said bellows is compressed so that fluid can be transmitted from said inlet opening to said chamber external of said bellows and vented alternately and sequentially.

4. The combination in accordance with claim 3 further comprising first conduit means communicating with said first fluid inlet, a first check valve in said first conduit means to'permitfluid' flow into the interior of said bellows within said housing, second conduit means communicating with said first fluid inlet, and a second check valve in said second conduit means to permit fluid flow from the interior of said bellows within said housing.

, References Cited in the file of this patent UNITED STATES PATENTS 

